The present invention relates to a data structure suitable for recording/playing back video data sent in digital broadcast or the like or stream data sent with a packet structure, a method of recording stream data using this data structure, and a method of playing back stream data recorded with this data structure.
(Description of Prior Art)
In recent years, TV broadcast has come into the era of digital broadcast. Accordingly, an apparatus for saving digital data of digital TV broadcast as they are irrespective of their contents, i.e., a so-called streamer, has been demanded.
The current digital TV broadcast uses an MPEG transport stream. In the future, an MPEG transport stream is projected to be used as a standard one in the field of digital broadcast using moving picture.
In such digital broadcast, the contents (mainly, video information) to be broadcasted are time-divided into groups of data each having a predetermined size (e.g., 188 bytes) called transport packets, and broadcast data is sent in units of transport packets.
As a streamer for recording digital broadcast data, a home digital VCR such as D-VHS (digital VHS) or the like is currently commercially available. A streamer using D-VHS directly records a broadcasted bitstream on a tape. For this reason, a plurality of programs are multiplexed and recorded on a video tape.
Upon playback, all data are output from the VCR to a set-top box (digital TV reception apparatus; to be abbreviated as an STB hereinafter) when they are played back either from the beginning or the middle of the tape. In this STB, a desired program is selected from the output data by user operation or the like. The selected program information is transferred from the STB to a digital TV receiver, and is played back (playback of video+audio and the like).
Since this D-VHS streamer uses a tape as a recording medium, it cannot attain quick random access, and it is difficult to quickly jump to a desired position of a required program so as to play it back.
As a promising candidate that can combat such shortcoming (difficulty of random access) of the tape, a streamer that uses a large-size disc medium such as a DVD-RAM or the like has been proposed. In this case, management data must be inevitably recorded together with broadcast data in consideration of random access, special playback, and the like.
(Problem)
Digital TV broadcast adopts an MPEG transport stream as a transmission method of stream data containing video information, and video information is sent while being combined in units of application packets each having, e.g., 188 bytes. By contrast, when a recording medium such as a DVD-RAM disc or the like that belongs to a DVD family is used, recording must be done in units of sectors, the minimum recording unit of which is 2,048 bytes. However, the following problems remain unsolved.
(1) A method of efficiently recording information of 188-byte application packets in units of 2,048-byte sectors is not settled yet.
(2) A method of playing back stream data recorded on an information storage medium while holding the reception timing of digital TV broadcast is not settled yet.
Furthermore, there is also a need for recording digital data which is transferred with a packet structure in a local area network (LAN) or a digital telephone line such as ISDN or the like using a streamer.
However, the following problem also remains unsolved.
(3) No versatile recording method that can record digital data other than digital TV is available.
(Object)
It is an object of the present invention to provide a data structure (recording format) on an information storage medium, which can efficiently record stream data on an information storage medium, and can play back stream data from an information storage medium while holding transfer timings between application packets received in digital TV broadcast.
It is another object of the present invention to provide a method of recording stream data using the data structure.
It is still another object of the present invention to provide a method of playing back stream data recorded with the data structure.